Electronic - Free

Proceedings

Out of Print

General notes:

Copies of the papers presented at, or published for DCC are available in
various ways. A paper printed in the proceedings will be available for
purchase in most cases in hard copy as the DCC proceedings. It will in
most cases also be available as an individual paper in PDF format as a
free download via a link below the abstract (where available) It may
also be available on CD-ROM. A paper printed in the proceedings may not
have been presented at the conference. Also a presentation at DCC may
not be in the printed proceedings. In those cases it may be available
on DVD, CD-ROM or as a MP3 download. Links to what is available will be
on the page specific to the particular year's DCC.

Unfortunately, all the video links below have been broken by a change of ISP for the host. The following will take you to an index at You Tube. (hint: the episode number in the broken link may help you find the video).

Abstract:
Modern Digital Amateur Television (DATV) techniques have brought the goal of
producing broadcast quality television within the reach of every amateur.
No longer are we faced with the demons of the old analogue system like ghosting,
poor contrast, improper sync pulse levels and poor colour. The considerable
improvements in spectral efficiency that DATV brings means also we can do more
with our crowded bands. The use of Forward Error Correction (FEC) techniques
also goes a long way to mitigate the adverse effects of the RF channel.

Until now the entry bar to DATV costs has been set very high. For those hams not able
to obtain surplus broadcast MPEG encoders and DVB-S transmitters it has meant paying
over US$1000 for equipment aimed at the ham radio market. This is all changing,
read about the exciting developments in low cost entry level DATV. In this paper
we describe our DATVexpress project to develop an inexpensive flexible
Digital Television transmitter for the Amateur Service using software defined radio
techniques and the power of the personal computer.

Abstract:
Of course stations and rovers have nearly perfect connectivity using the
existing national APRS network on the established national channel of 144.39.
But the problem is, it is hard to see who is involved in the event among
the other thousands of permanent users there. Or at other times, a temporary
digipeater may be needed because certain key digipeaters might be down during
an emergency and a station needs to use other surrounding stations to get out.
For these reasons, it is nice to have a backup, shadow ad-hoc networking
capability built into every packet station that is always on and ready to be used.

Abstract:
Operating PSK-31 without a PC has been a big capability of the
NUE-PSK Digital Modem for several years. RTTY support was added
along the way and even more advanced digital modes continue to
be in development. But modem owners are also clamoring for support
of the oldest digital mode of them all ... CW!

This paper describes our open source implementation of this
venerable digital mode as an implementation of the Goertzel DSP
filtering technique used on the modem’s dsPIC33F processor. Innovative
approaches are used to solve the classic problems of speed tracking
(up to 50 wpm!), adaptive weighting adjustment, and tuning.

Abstract:
This paper discusses a means of using the android smartphone as a Global
Positioning System (GPS) receiver unit to provide serial location data
to an APRS beacon transmitter. Using an application I developed, an
android smartphone with a GPS receiver sends its location to a laptop
computer via Bluetooth. Through a program written for the laptop the
position data is sent to a serial port in NEMA-0183 format. This serial
data can then be sent to a TNC/radio to transmit an APRS beacon with location
information. After appropriate digipeating, the beacon information reaches
an I-gate station and appears on the APRS Internet System. Although an
APRS App is available for android smartphones, which puts the location
information directly on the Internet, that application is not useful
when there is no cellphone coverage, Wi-Fi access, or one does not want
to pay for the android data plan.

Abstract:
Bluetooth has become the standard technology for external interfacing to laptop PCs and
mobile devices. This paper describes a number of ways to implement serial data
communication using the Roving Networks Bluetooth devices.

Abstract:
A case study describing real-time APRS web mapping support for Lead and
Last runner tracking during the 2011 Athens Ohio Marathon. Objectives were:
(a) to provide real-time web-based runner location maps for race officials,
emergency services, and spectators without the use of JAVA or Flash;
(b) to support a wide range ofweb-capable wireless devices; and
(c) to optimize display speeds while reducing bandwidth demands.

Abstract:
As I reported at the 2009 Digital Communications Conference in Elk Grove, Illinois, the
agenda for what was then the 2011 World Radiocommunication Conference includes an item of
potential concern to Amateur Radio experimenters:

1.19 to consider regulatory measures and their relevance, in order to enable the introduction
of software-defined radio and cognitive radio systems, based on the results of ITU-R studies,
in accordance with Resolution 956 (WRC-07);

Abstract:
Previously the authors gave an overview of a Delay Tolerant Network
Convergence Layer implementation that operates over Connected Mode AX.25,
and detailed the results of some performance tests using it to transfer
data over Amateur Radio channels. These results were compared to both a
native AX.25 and a TCP/IPover-AX.25 implementation. The investigation of
TCP/IP was undertaken because, while it is generally accepted that TCP
is unsuited to wireless links, it has become the dominant protocol in
real-world applications, with over 50% of internet traffic now accounted
for by TCP over port 80 [1].

As some issues were highlighted in experiments leading to the authors
prior publication, these have been worked on and have been largely
resolved. It was also found that our model for an ideal AX.25
communications channel had deficiencies, so a correction is offered.
Additionally, we also tested our Convergence Layer alongside a TCP/IP
over AX.25 implementation on both a 1200 and 9600 baud point-to-point
link and give comparative results between our Convergence Layer
implementation and TCP/IP. Real-world behaviour of the data link still
diverges from the model, but the authors provide some possible reasons
for this.

A Further Comparison of Different TCP/IP and DTN Protocols
over the D-STAR Digital Data Modeby
John Ronan EI7IG and
Cathal O'Connor
- Waterford Institute of Technology

Abstract:
This work examines the performance of the Digital Smart Technologies for
Amateur Radio - Digital Data mode with various IP and non-IP based protocols.
A throughput comparison was performed between TCP/IP and two DTN convergence
Layers. The experimental results show that the DTN NORM Convergence Layer
exhibits better performance than TCP/IP and TCP based convergence layers, and,
furthermore appears to be more suited for use on difficult radio links.

Abstract:
Codec 2 is an open source, low bit rate codec for speech over HF/VHF digital
radio. Most low bit rate codecs are.proprietary, closed source, and require
licensing fees. Codec 2 is unique in that it is open source, allowing
experimentation and modification. It fills a gap in open source, free-as-in-speech
voice codecs beneath 5000 bit/s and is released under the GNU
Lesser General Public License (LGPL).

This paper describes the motivation for Codec 2, status, and future plans.
The Codec algorithm is described using figures, avoiding high level maths
and Digital Signal Processing (DSP) theory.

Abstract:
Why use a phone for a high-capability spacecraft? A phone can increase
on-orbit processor capability by a factor of 10-100. A phone can
also decrease cost by a factor of 10-1000. Learn the results of their testing.

Abstract:
What a year it has been. Last September, we successfully demonstrated
the BiLiF hardware at the 29th.TAPR show in Portland, Oregon. More
recently, the MDSR team has worked on the software transceiver; MDSR
(Modulation – Demodulation Software Radio). Since the BiLiF hardware
can be adapted to any 455kHz IF transceivers (adaptations were also
made for the 9MHz IF of the IC-706 series transceivers), the software
is also designed to be flexible and user friendly. This software can
be downloaded from the MDSR website or Yahoo user group and is free
as long as it is used for amateur radio purposes.

Abstract:
In many countries mobile phone calls are very expensive; costing $0.25/min
when the Average Income is $1.52/day. Mesh WiFi provides simple advantages over
Regular WiFi. Mesh Potato can provide a solution for poor countries. The first
real world deployment of Village Telco was in Timor, near Indonesia. Learn how
this project is really helping people every day!

Abstract:
So just what is "Digital Mode Communication?" Results of a survey of some
popular digital modes ... What the heck are all those weird-sounding
stations I hear as I tune around the bands? From Packet, RTTY, and
PSK31...through MFSK16, Olivia, and JT65. This is a good introduction to
ham radio digital modes and programs to run them on your rig.

Abstract:
A good introduction to D-STAR (Digital Smart Technologies for Amateur
Radio);
providing simultaneous digital voice and data on the same signal. Includes an
overview of the D-RATS communication tool.

Abstract:
APRS is for human to human info exchange! A single channel info-resource!
This introduction reviews the capabilities of APRS and the current radios
for APRS. The presentation also overviews FINDU.COM.

Abstract:
The OpenHPSDR Project is a modular, open source hardware and software platform
for development of all components of a Software Defined Radio.
The presentation provides an overview of the OpenHPSDR architecture and modules
and the openHPSDR project status as of September, 2011...including the
availability of the modules.

Abstract:
FlexRadio has doubled the shipments of Software Defined Radio (SDR) units and
doubled their office space. The presentation includes discussion of WBIR software
written by N4HY to allow rejection of near-in images with direct-conversion.

Abstract:
An introduction provides an overview of Radio Architectures and Real-world
impairments. The next section covers interpreting Spectrum Analyzer
measurements and SNR-CNR. The following section digs deeper into
Radio Architectures. The last section digs deeper into Hardware Inherent
impairments and Architecture Specifc impairments.

Abstract:
Mark Braunstein WA4KFZ proposes changes that could make D-Star even better.
These proposals including adding Forward Error Correction (FEC) to data-only
modes, providing a 4800 bps data-only mode, and building new models of radios
equipped with a D-STAR-only display mode. There are many other suggestions
provided as "food fo thought".

Abstract:
This presentation provides a status report on automatic link establishment, which is referred
to as ALE. The key question today is how does ALE work and how can it be integrated into
automatic voice linking and digital messaging system. This becomes a very important question
for emergency communications.

Abstract:
APRS can ptovide human-to-human info exchange and single channel info-resource!
APRS-messaging is a Universal Ham Radio Text Messaging Initiative.
APRS can provide universal VOIP connections via APRS signaling.
APRS is not just for the Maps...its the network!

Abstract:
This round table of ideas for achieving Universal Ham Radio Contact via call sign
discusses many different approaches; including AVRS, APRStt (touchtone), a
call sign database called ircDDB used in D-Star network,and several other approaches.